Resorcinol derivatives are known to be useful for a variety of purposes. For example, in the cosmetic field, resorcinol derivatives have been used as skin lightening agents. The use of resorcinol derivatives as skin lightening agents is described in European Patent Application EP 904,774, published Mar. 31, 1999; U.S. Pat. No. 5,468,472, issued Nov. 21, 1995; U.S. Pat. No. 5,399,785, issued Mar. 21, 1995; European Patent Application EP 623,339, published Nov. 9, 1994; JP 5-4905, published Jan. 14, 1993; and European Patent Application EP 341,664, published Nov. 15, 1989.
Resorcinol derivatives have also been used as dandruff control agents (JP 4-169516, published Jun. 17, 1992); as anti-acne agents (JP 4-169511, published Jun. 17, 1992); as potentiators of anti-microbial compounds (U.S. Pat. No. 4,474,748, issued Oct. 2, 1984); as anti-browning agents for foods (U.S. Pat. No. 5,304,679, issued Apr. 19, 1994); and in the preparation of photographic dye images (U.S. Pat. No. 3,756,818, issued Sep. 4, 1973).
The present invention provides an improved process for preparing 4-substituted resorcinol derivatives. The present invention further provides intermediate compounds useful in preparing such resorcinol derivatives, as well as processes for preparing the intermediate compounds. The improved process of the present invention is easier to use than standard methods for preparing resorcinol derivatives in large quantities. In addition, the improved process of the present invention results in a higher yield of final product than standard methods.